Conventionally, in information processing systems, tunnel communication devices, tunnel communication methods, and programs for encapsulating a packet to make a tunnel communication, plural points connected to a communication line such as Internet could communicate with each other as if they are connected to each other through an exclusive line, by using a technology of a virtual private network (hereinafter, referred to as “VPN). This configuration is disclosed in Charlie Scott's Document (“Virtual Private Networks, Second Edition” written by Charlie Scott, Paul Wolfe, and Mike Erwin, O'REILLY, December of 1998, P1˜9 and P11 to 22).
However, in the conventional information processing system encapsulating a packet to make a tunnel communication, a complex setup for a device serving as a connection point such as a router is required to connect plural local area networks and a user should make such a setup. Therefore, if the user cannot set up a network well, it is difficult to make a communication between plural points.